Push-pull type remote control cable



A ril 6, 1965 J. B. HURLOW PUSH-PULL TYPE REMOTE CONTROL CABLE Filed May 2, 1960 John B. Hurlow INVENTOR.

BY /F W AH by.

United States Patent r 3,176,538 PUSH-PULL TYPE REMOTE CONTRGL CABLE John B. Harlow, 10.10 Fir Park Lane, Tacoma, Wash. Filed May 2, 1960, Ser. No. 25,942 5 Claims. (Cl. 74-50'1)v This invention relates to push-pull type cables of the class employed for controlling apparatus from a remote station.

In one widely used type of push pull cable, the core comprises wire strands armored with a tight wire wrapping. In this construction the strands take the tension forces and the spiral wrapping the compression forces which are applied to the cable during use.

The core then is sheathed in a sheath consisting of three overlying wire wrappin-gs, the innermost being arranged in a tight, slow spiral; the intermediate in a tight, fast spiral; and the exterior in a spaced slow spiral.

While cable having this construction has many applications, it is expensive to manufacture and is subject to binding in certain types of installations.

It is the general object of the present invention to provide a push-pull type remote control cable which is simple and inexpensive to manufacture, of wide application, and remarkably free from any binding tendency even when laid around sharp corners.

The manner in which the foregoing and other objects of this invention are accomplished will be apparent from the accompanying specification and claims considered together with the drawings, wherein:

FIG. 1 is a view in elevation of a section of the herein described cable with the various layers broken away to show the interior construction; and

FIG. 2 i a sectional view taken along line 2-2 of FIG. 1.

In general, the push-pull type remote control cable of my invention comprises a core of wire strands armored with fused flexible plastic. A sheath overlies the movable inner core, and comprises a flexible plastic tube wrapped with spiralled wire. Thus the flexible, plastic armor of the core is in sliding contact with the flexible, plastic tube of the sheath, providing a unit having an exceptionally low coefficient of friction and very high resistance to abrasion even though its installation requires that it be bent severely around corners. To achieve this result, it is necessary that the plastic armor of the core be used toget er with the plastic tube. The same result i not obtained, for example, when a core armored in plastic is moved in a sheath the inner member of which comprises flat-coiled steel wire.

As is seen in the drawings, the core member of the herein described remote control cable comprises a plurality of wire strands 10, twisted tightly together. These are armored with a plastic overlayment 12 which preferably comprises polytetrafluorethylene (Teflon), because of its self-lubricating and wear qualities.

It is preferred to extrude the plastic overlayment about the wire strand core so that the softened plastic will flow around and between the strands, locking them together in their preferred arrangement. As a result, a long-wearing armored core is formed which can not be disarranged by the application of either tension or compression forces within the limits of strength of the materials employed.

Surrounding the core is a sheath the innermost layer of which comprises a tube 14, also made of flexible plastic. Polymerized hexamethylenediamine adipamide (nylon) is preferred for this application because of its selflubricating characteristics. Suificient clearance is afforded between plastic armor 12 of the core and tube 14 of the sheath so that one will slide easily relative to the other.

Although polytetrafluorethylene and polymerized hexamethylenediamine adipamide have been indicated as preferred plastics, plastic materials for use in the present invention, other suitable plastics may be used. Among these may be listed as examples polyethylene, the polyvinyl plastics, and Dacron.

Tube 14 is wrapped with wire, preferably with two wire wrappings. The innermost wire wrapping 16 is composed of a multiplicity of wire strands arranged close to each other in a fast spiral. The outer wrapping 13 comprises a single wire strand arranged in a slow, spaced spiral, thereby supplying a sheath of great strength.

Thus it is apparent that by this invention I have provided a push-pull type remote control cable which is of relatively simple, inexpensive construction. Nevertheless, it surprisingly has been found :to move heavy loads far more readily than does the all steel cable which is its counterpart. Thus, by tests I have found that Whereas a force of 1700 pounds is required to move a load of 1000 pounds using an all steel conventional cable, but 1100 pounds are required to move the same load using the presently described plastic-armored cable, wherein two plastic surfaces are in sliding contact with each other.

It is to be understood that the form of my invention herein shown and described is to be takenas a preferred example of the same and that various changes in the shape, size and arrangement of parts may be resorted to without departing from the spirit of my invention or the scope of the subjoined claims.

Having thus described my invention, I claim:

1. A push-pull type remote control cable assembly comprising a core of wire strands armored with a fused flexible plastic overlayment adapted to transmit tension and compression forces without disarrangement, the overlayment of the core having a smooth, continuous outer surface, and a sheath slidably receiving the plastic overlayment, the sheath comprising a flexible plastic tube wrapped exteriorly with wire and having a smooth continuous inner surface, the cable assembly thus being flexible and the core thereof being in free sliding contact with the plastic tube of the sheath in flexed conditions of the assembly.

2. The cable of claim 1 wherein the armor for the wire strands of the core is polyitetrafluore thylene providing a low friction sliding contact with the tube.

3. The cable of claim 1 wherein the plastic tube of the sheath comprises polymerized hexamethylenediamine adipamide providing a low friction sliding contact with the core overlayment.

4. The cable of claim 1 wherein the armor for the wire strands of the core is polytetrafluorethylene and the flexible plastic tube of the sheath comprises polymerized hexamethylenediamine adipamide providing a low friction sliding contact between the overlayment and the tube.

5. A push-pull type remote control cable assembly comprising a core of wire strands armored with a fused flexible plastic overlayment adapted to transmit tension and compression forces without disarrangement, the overlayment of the core having a smooth, continuous outer surface, a sheath slidably receiving the plastic overlayment, the sheath comprising a flexible plastic tube having a smooth, continuous inner surface, a first wrapping of wire on the tube arranged in a fast spiral, and a second wrapping of wire on the first wrapping arranged in a slow spiral, the cable assembly thus being flexible and the core thereof being in free sliding contact with the plastic tube of the sheath in flexed condition of the assembly.

(References on following page) References Cited by the Examiner UNITED STATES PATENTS Burd et a1. 13813O Beed 74- 501 X Schroeder 745()2 Cordora et a1 74-501 Bratz 74--501 Morse 138- -134 X Bratz 74-501 3,063,303 11/62 (Zadwallader 74-501 3,086,557 4/63 Peterson 138-133 FOREIGN PATENTS 1,207,292 8/59 France. 1,224,692 2/ 60 France. 1,237,474 6/60 France.

811,607 4/59 Great Britain.

BROUGHTON G. DURHAM,-Primary Examiner. 

1. A PUSH-PULL TYPE REMOTE CONTROL CABLE ASSEMBLY COMPRISING A CORE OF WIRE STRANDS ARMORED WITH A FUSED FLEXIBLE PLASTIC OVERLAYMENT ADAPTED TO TRANSMIT TENSION AND COMPRESSION FORCES WITHOUT DISARRANGEMENT, THE OVERLAYMENT OF THE CORE HAVING A SMOOTH, CONTINUOUS OUTER SURFACE, AND A SHEATH SLIDABLY RECEIVING THE PLASTIC OVERLAYMENT, THE SHEATH COMPRISING A FLEXIBLE PLASTIC TUBE WRAPPED EXTERIORLY WITH WIRE AND HAVING A SMOOTH CONTINUOUS INNER SURFACE, THE CABLE ASSEMBLY THUS BEING FLEXIBLE AND THE CORE THEREOF BEING IN FREE SLIDING CONTACT WITH THE PLASTIC TUBE OF THE SHEATH IN FLEXED CONDITIONS OF THE ASSEMBLY. 